Plugging undesired openings in fluid conduits

ABSTRACT

A method of plugging at least one undesired opening in a fluid conduit can include introducing one or more plugging devices into the conduit, conveying the plugging devices by flow to the opening, and blocking the flow through the opening with the plugging devices. A system for plugging at least one undesired opening in a fluid conduit can include a deployment apparatus configured to introduce one or more plugging devices into the conduit, a sensor that measures a physical parameter indicative of leakage from the conduit, and a controller that activates an actuator of the deployment apparatus in response to receipt from the sensor of an indication of leakage from the conduit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage under 35 USC 371 of InternationalApplication No. PCT/US18/29395, filed on 25 Apr. 2018, which claimspriority to U.S. Provisional Application No. 62/540,462 filed 2 Aug.2017 and U.S. Provisional Application No. 62/489,923 filed 25 Apr. 2017.The entire disclosures of these prior applications are incorporatedherein by this reference.

TECHNICAL FIELD

This disclosure relates generally to blocking flow through a leak pathin a fluid conduit and, in one example described below, moreparticularly provides for use of a plugging device to plug undesiredopenings in fluid conduits.

BACKGROUND

It can be difficult to mitigate leakage from a fluid conduit that ispart of a continuously operating process. Typically, the process must beterminated, the leakage fixed or the vessel replaced, and then theprocess must be re-started. These mitigation efforts can be costly andtime-consuming.

Therefore, it will be appreciated that improvements are continuallyneeded in the art of plugging undesired openings in fluid conduits.These improvements can be useful even in situations in which the fluidconduit is not part of a continuously operating process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representative cross-sectional view of an example of asystem and associated method which can embody principles of thisdisclosure, in which a fluid is leaking from a fluid conduit.

FIG. 2 is a representative cross-sectional view of the system andmethod, in which a plugging device has engaged an undesired opening inthe conduit, thereby plugging the opening.

FIG. 3 is a representative cross-sectional view of the system andmethod, in which the plugging devices are retrieved by use of a filter.

FIG. 4 is a representative cross-sectional view of another example ofthe system and method, in which the plugging devices have differentbuoyancies.

FIG. 5 is a representative cross-sectional view of the system andmethod, in which the plugging devices have different sizes.

FIG. 6 is a representative cross-sectional view of an example of theplugging device, in which the plugging device includes a detectiondevice.

FIG. 7 is a representative cross-sectional view of an example of adeployment apparatus that may be used with the system and method.

FIG. 8 is a representative cross-sectional view of the deploymentapparatus connected to the fluid conduit.

FIGS. 9A & B are representative side view of examples of the pluggingdevice.

FIG. 10 is a representative side view of another example of the pluggingdevice.

FIGS. 11A & B are representative partially cross-sectional views of thesystem and method, in which the plugging device is used to plug anopening in another fluid conduit.

FIGS. 12-14 are representative side views of examples of the pluggingdevice with a retainer.

FIGS. 15 & 16 are representative partially cross-sectional views ofadditional examples of the deployment apparatus.

FIGS. 17-19 are representative views of additional examples of theplugging device.

FIGS. 20 & 21 are representative partially cross-sectional views ofanother example of the system and method.

DETAILED DESCRIPTION

Example methods described below allow inadvertent or otherwise undesiredopenings in fluid conduits to be blocked permanently or temporarily in avariety of different applications. Certain flow conveyed plugging deviceexamples described below can be made of a fibrous material and maycomprise a central body, a “knot” or other enlarged geometry forblocking flow through the undesired openings.

The plugging devices may in some examples be conveyed through a conduitwith pumped fluid. Fibrous material extending outwardly from a body of aplugging device can “find” and follow the fluid flow, pulling theenlarged geometry or fibers into a restricted portion of a leakage flowpath, causing the enlarged geometry and additional strands to becometightly wedged into the flow path, thereby sealing off fluidcommunication.

The conduit may be any type of pipeline, process piping, plumbing, fluidsupply line, tubing or other fluid conduit.

The plugging devices can be made of degradable or non-degradablematerials, or a combination of degradable and non-degradable materials.The degradable materials can be either self-degrading, or can requiredegrading treatments, such as, by exposing the materials to certainacids, certain base compositions, certain chemicals, certain types ofradiation (e.g., electromagnetic or “nuclear”), or elevated temperature.The exposure can be performed at a desired time, such as, by spotting orcirculating a fluid in the conduit so that the material is exposed tothe fluid.

In some examples, the material can be an acid degradable material (e.g.,nylon, etc.), a mix of acid degradable material (for example, nylonfibers mixed with particulate such as calcium carbonate), self-degradingmaterial (e.g., poly-lactic acid (PLA), poly-glycolic acid (PGA), etc.),material that degrades by galvanic action (such as, magnesium alloys,aluminum alloys, etc.), a combination of different self-degradingmaterials, or a combination of self-degrading and non-self-degradingmaterials.

Multiple materials can be pumped together or separately. For example,nylon and calcium carbonate could be pumped as a mixture, or the nyloncould be pumped first to initiate a seal, followed by calcium carbonateto enhance the seal.

In certain examples described below, the plugging device can be made ofknotted fibrous materials. Multiple knots can be used with any number ofloose ends. The ends can be splayed, frayed (e.g., finely dividedstrands or fibers) or un-frayed. The fibrous material can be rope, yarn,fabric, metal wool, cloth or another woven or braided structure.

The plugging device can be used to block flow through any leak paths ina conduit and associated piping (such as, leaking threaded, gasketed,sealed or flanged connections, corrosion holes, cracked or otherwisedamaged areas, etc.). Any opening or leak path through which fluid flowscan be blocked with a suitably configured plugging device. For example,an opening between two different volumes (such as, tubes and reservoirin a heat exchanger), could be plugged using the plugging device.

The plugging device can be used to block flow through any leak path in aconduit designed to treat fluids, with reduced velocities, traps, trays,gas separation or any fluid density separation means. Leak paths mayinclude any undesirable escape of fluid from the contained system andmay occur in threaded, flanged, welded, corroded (internal or external)walls or connections to or that make up a conduit-like device.

The plugging device may be used to seal openings in steam generation,handling and distribution equipment. Some examples include steamgenerators and associated steam passageways, such as heat exchangers.Steam distribution equipment may include steam flood piping in oil fieldsteam injection applications, where steam is injected into a formationand then produced (known to those skilled in the art as “huff and puff”enhanced recovery operations), and also steam flood operations and SAGD(steam assisted gravity drain) operations. Geothermal well and pipeapplications may also benefit from use of the plugging devices describedherein.

The plugging device may be used for sealing off openings and leak pathsboth on surface and sub-surface, as well as surface and sub-sea wellsiteoperations (such as, onshore or offshore drilling, completion andproduction operations). For example, a method could include releasingplugging devices to seal a leak in a blowout preventer stack, or any ofits components (such as, pipe rams, blind rams, annular preventer,seals, gaskets, flanges, threaded connections, etc.).

The plugging device may be used for sealing off openings and leak pathsin riser pipes, both subsea and above water level. The plugging devicemay be used for sealing off openings and leak paths in drilling,completion, stimulation, conformance, injection, production or workoverrig operations (whether onshore, floating or stationary platforms,offshore, etc.).

A volume of plugging devices can be introduced into a given conduit, andthen can be captured at a downstream location (for example, in ascreen-like device or filter). Once captured they may be re-circulatedthrough the conduit any number of times, until the need no longer existsor scheduled maintenance has been completed.

The plugging devices may be released into the conduit in response to anemergency or hazardous situation. For example, an emergency dispensingdevice could be pre-loaded with a quantity of plugging devices so that,when an emergency situation occurs or is detected, the plugging devicesare released into the conduit. The plugging devices may be releasedautomatically (e.g., in response to a sensor detecting an emergency orhazardous situation), or the plugging devices may be released manuallyby an operator. For example, the dispensing device could be incommunication with a fire detection system or a leak detection system ata refinery or processing plant. Leak detection could be performed forfluid conduits under roads and highways, or at stream or rivercrossings, etc.

The materials of the plugging device can be selected for the givenproduct/process flow through the conduit. In some examples, the fluid inthe conduit could be glycol and/or amine type treating chemicals, oil,salt water or gas condensates. In other examples, gas may be present inthe conduit.

The density of the plugging device material can be selected to ensuredispersion of multiple plugging devices in the conduit, or to ensurethat a plugging device will be positioned at a level of the opening tobe plugged. Floating, sinking or neutrally buoyant plugging devices maybe used. Plugging device materials may be combined with hollow spheresto enhance buoyancy, or more dense solid materials to “sink” theplugging devices.

Plugging devices introduced into a conduit can have a variety ofdifferent sizes for a corresponding variable opening size potential. Theopening could be anything from a small pin-hole leak created by externalor internal corrosion, to a failed weld or crack from repeated heat dutycycling.

The plugging device may also be embedded with any of a variety ofdifferent types of detection technology. This technology could compriseradioactive material (preferably with a short half-life) easily locatedwith gamma ray equipment, or magnetic material easily identifiable withuse of a magnetic field. Ultra-sonic, radio frequency or infraredtechnology may be used to detect and identify the plugging device. Anultrasonic or RFID (radio frequency identification) transmitter may beembedded in the plugging device.

Representatively illustrated in FIG. 1 is a system 10 and associatedmethod which can embody principles of this disclosure. However, itshould be clearly understood that the system 10 and method are merelyone example of an application of the principles of this disclosure inpractice, and a wide variety of other examples are possible. Therefore,the scope of this disclosure is not limited at all to the details of thesystem 10 and method described herein and/or depicted in the drawings.

In the FIG. 1 system 10, a fluid 12 is flowed through a conduit 14. Anopening 20 in a wall of the conduit 14 allows some of the fluid 12 toleak out of the conduit.

Note that it is not necessary in keeping with the principles of thisdisclosure for the opening 20 to be formed through a wall of the conduit14, for the fluid 12 to enter the conduit from one end and exit theconduit via another end, or for the fluid to leak to an exterior of theconduit. In other examples, the opening 20 could be at a threadedconnection or in a component other than the conduit 14, the fluid 12could enter and exit the conduit 14 via other intersecting conduits,ports or other flow paths, and the fluid could pass between otherwiseisolated regions internal to the conduit 14 or other process equipment.Thus, the scope of this disclosure is not limited to any of the detailsof the system 10, conduit 14 or other elements as described herein ordepicted in the drawings.

In the FIG. 1 example, a number of flow conveyed plugging devices 60have been released into the conduit 14. Flow of the fluid 12 through theconduit 14 carries the plugging devices 60 also through the conduit.

If only a single opening 20 is to be plugged, one or more pluggingdevices 60 may be introduced into the conduit 14. If there are a knownnumber of openings 20 to be plugged, that known number of pluggingdevices 60, or more, may be introduced into the conduit 14. If thenumber of openings 20 to be plugged is unknown, a selected number ofplugging devices 60 may be introduced into the conduit 14, effectivenessof the plugging may be evaluated, and additional plugging devices may beintroduced into the conduit if all openings have not yet been plugged.

In some examples, the plugging devices 60 may be introduced into theconduit 14 only when it is desired to plug one or more openings 20. Inthese examples, release of the plugging devices 60 is initiated inresponse to a selected stimulus (such as, a detected pressure loss dueto release of the fluid 12, observation or other detection of a leak,reduced flow, etc.).

In other examples, the plugging devices 60 may be continuouslycirculated or periodically (e.g., at regular predetermined intervals) orintermittently introduced into conduits or other process equipment, as apreventative measure. In these examples, a plugging device 60 will pluga newly-occurring opening 20 soon after it occurs, without release ofplugging devices being initiated by the occurrence of the opening.

As depicted in FIG. 2, one of the plugging devices 60 has sealinglyengaged the opening 20. Leakage of the fluid 12 from the conduit 14 is,thus, prevented.

The remaining plugging devices 60 (if any) can be flowed downstream ofthe opening 20 with the fluid 12. In examples in which the pluggingdevices 60 are continuously, intermittently or periodically flowedthrough the system 10, plugging devices may accordingly continuously,intermittently or periodically flow through the conduit 14.

As depicted in FIG. 3, a strainer, screen, filter 24 or other apparatusmay be used to retrieve the plugging devices 60 from the conduit 14 orother process equipment. In FIG. 3, the filter 24 is connected to theconduit 14, so that plugging devices 60 flowing through the conduit 14will be separated from flow of the fluid 12. The retrieved pluggingdevices 60 can be discarded or they can be reintroduced into the system10.

In an example of the system 10 depicted in FIG. 4, the conduit 14 is inthe form of a tank, and the fluid 12 comprises a liquid contained in thetank. However, the opening 20 in a wall of the conduit 14 permits someof the fluid 12 to leak from the conduit.

In the FIG. 4 example, plugging devices 60 having a variety of differentbuoyancies in the fluid 12 are introduced into the conduit 14. On theleft-hand side of FIG. 4, some of the plugging devices 60 are depictedas being in line vertically, to demonstrate that the plugging devicescan be vertically distributed in the fluid 12 along an entire distancefrom a bottom of the conduit 14 to a top of the conduit.

The plugging devices 60 may have positive, negative and neutralbuoyancies. If a vertical height to the opening 20 is known, a buoyancyof a plugging device 60 may be selected, so that the plugging devicewill “float” in the fluid 12 at that vertical height. Ranges ofbuoyancies may be selected to cause multiple plugging devices 60 to“float” near the bottom of the conduit 14, near the top of the conduit,or at a selected range of depths in the fluid 12.

If the plugging devices 60 are continuously, intermittently orperiodically flowed through the system 10 for preventative purposes, theuse of a variety of different buoyancies is desirable, since the depthof an opening 20 will typically be unknown at the time the pluggingdevices are introduced into the system.

A plugging device 60 may in some examples be provided with a “bladder”type core that changes density based on pressure and/or temperature.This would allow the device to become much denser under pressure andmore buoyant when pressure is bled off. Some examples can include: 1) Ina conduit under “normal” conditions the devices could sit on bottom, andthen automatically engage as a leak causes a pressure decrease. 2) In anoil and gas well, devices could be less buoyant when being pumpeddownhole under fracturing conditions, and then become more buoyantduring flow back of the well for easier clean up and removal. Thebladder could be filled with a gas, such as CO₂, that converts to aliquid under pressure, and then to a gas when the pressure is reduced,etc., with a large phase envelope. The reverse of this may have someapplication, as well (e.g., change in phase from gas to liquid).Pressure and or temperature change could reduce the buoyancy at apre-determined set point, and thereby cause the device to sinkharmlessly out of the way of operations and or fluid flow if desired.

In an example of the system 10 depicted in FIG. 5, plugging devices 60having a variety of different sizes are disposed in the conduit 14. Theopening 20 permits some of the fluid 12 to leak from the conduit 14.

If a size (such as, a diameter, width, etc.) of the opening 20 is notknown, the use of a variety of different sizes of the plugging devices60 ensures that at least one of the plugging devices will have anappropriate size to block flow through the opening. If the pluggingdevices 60 are continuously, intermittently or periodically flowedthrough the system 10 for preventative purposes, the use of a variety ofdifferent sizes of plugging devices is desirable, since the size of anopening 20 will typically be unknown at the time the plugging devicesare introduced into the system.

As depicted in FIG. 6, an example of a plugging device 60 includes adetection device 28 for detecting a presence, characteristic and/oridentity of the plugging device. The detection device 28 enables theplugging device 60 to be detected at any point in the system 10 usingsuitable detection equipment.

The detection device 28 may be “passive” in that it does not activelytransmit a signal for detection by a receiver. Instead, the detectiondevice 28 could propagate a magnetic field (in the case of a magnet),radioactivity (in the case of a radioactive material) or otherdetectable characteristic due to a material of the device. Othercharacteristics (such as, density, etc.) of a detection device 28 may bedetectable to indicate the presence, characteristic or identity of thecorresponding plugging device 60.

The detection device 28 may be “active” in that it is configured totransmit a distinct signal to be detected by the detection equipment.For example, the detection device 28 could comprise an acoustic orultrasonic transmitter, a radio frequency transmitter, an infrared lightsource, or any other device capable of emitting a signal detectable bythe detection equipment.

The detection device 28 may be at times passive, and at other timesactive. For example, the device 28 could comprise a radio frequencyidentification (RFID) device that is initially passive, but becomesactive in response to scanning by an RFID reader. A signal emitted bythe RFID device could include information, such as, a unique identity ofthe plugging device 60, a material, size, density, buoyancy or othercharacteristic of the plugging device, etc.

In situations, such as that depicted in FIG. 2, in which a pluggingdevice 60 has engaged an opening 20 in a conduit 14, the position andidentity of the plugging device 60 may be conveniently determined byconveying a pipeline “pig” through the conduit. The pig can be equippedwith detection equipment that can receive the signal transmitted fromthe device 28, or can otherwise detect the presence of the device 28.Use of the pig with the detection equipment can be beneficial, forexample, in circumstances in which the opening 20 is not visible (e.g.,the opening could be hidden by insulation, or the conduit could beunderground), or in which the conduit 14 is too long to readily surveythe entire length of the conduit.

As depicted in FIG. 7, an example of a deployment apparatus 30 is usedto deploy the plugging devices 60 into the conduit 14 for transport withthe fluid 12 in the system 10. In this example, the deployment apparatus30 includes a container 32 for storing the plugging devices 60, and anactuator 34 for dispensing the plugging devices from the container intothe conduit 14.

In other examples, the apparatus 30 could deploy the plugging devices 60directly into the conduit 14 or other process equipment having theopening 20 to be plugged. The plugging devices 60 may be deployedcontinuously, periodically, intermittently, or in response to detectionof a selected stimulus.

As depicted in FIG. 8, the apparatus 30 is activated by a controller 36in response to reception of an indication that the fluid 12 is leakingfrom the conduit 14. In this example, a sensor 38 measures a physicalproperty, and measurements are transmitted to the controller 36, whichdetermines (based on appropriate algorithms) whether the measurementsindicate that the opening 20 is present.

For example, the sensor 38 could comprise a pressure sensor, a flow ratesensor or a temperature sensor (or any combination thereof). Leakage ofthe fluid 12 from the conduit 14 could, thus, be indicated by a decreasein pressure in the conduit 14, an increase in flow rate into theconduit, or an increase in temperature in the conduit. Other sensorexamples could include “fire eyes” or fire detection sensors forplant/refinery applications.

If the controller 36 determines that the opening 20 is present, or thatthe fluid 12 is leaking from the conduit 14, the actuator 34 of theapparatus 30 is activated to release one or more of the plugging devices60 into the conduit 14. The apparatus 30 may be deactivated by thecontroller 36 when the controller determines that the opening 20 isplugged or the fluid 12 is no longer leaking from the conduit 14.

The controller 36 can also be connected to a detector 40 that can detectthe presence and identity of each of the plugging devices 60. As aplugging device 60 flows past the detector 40, the detector detects thepresence of the device (e.g., due to the detection device 28 and anysignal transmitted by the detection device), and in some examples candetect the identity of the plugging device (such as, a serial number orother unique identifier associated with the plugging device) and/orcertain characteristics of the plugging device (such as, size,configuration, density, material, buoyancy, etc.).

This information can be used by the controller 36 to determine whetherappropriate plugging devices 60 have been released from the deploymentapparatus 30 (e.g., plugging devices having appropriate identities andcharacteristics), whether additional plugging devices should bedeployed, and whether deployment of the plugging devices should beceased.

In some examples, the sensor 38, detector 40 and controller 36 maycomprise the detection equipment described above for detecting thedetection device 28 in the plugging device 60. For example, the sensor38 or detector 40 could comprise an RFID reader, a radiation detector,an acoustic or ultrasonic receiver, an infrared light sensor, or anyother device capable of detecting a signal emitted by the detectiondevice 28.

Referring additionally now to FIG. 9A, an example of a flow conveyedplugging device 60 that can incorporate the principles of thisdisclosure is representatively illustrated. The device 60 may be usedfor any of the plugging devices in the system 10 and method examplesdescribed herein, or the device may be used in other systems andmethods.

The device 60 example of FIG. 9A includes multiple fibers 62 extendingoutwardly from an enlarged body 64. As depicted in FIG. 9A, each of thefibers 62 has a lateral dimension (e.g., a thickness or diameter) thatis substantially smaller than a size (e.g., a thickness or diameter) ofthe body 64.

The body 64 can be dimensioned so that it will effectively engage andseal off a particular opening in a conduit or other process equipment.For example, if it is desired for the device 60 to seal off an openingwith known characteristics, the body 64 can be formed so that it issomewhat larger than a diameter, width or other size of the opening. Ifit is desired for multiple devices 60 to seal off multiple openingshaving a variety of dimensions (such as holes caused by corrosion of theequipment), then the bodies 64 of the devices can be formed with acorresponding variety of sizes.

In the FIG. 9A example, the fibers 62 are joined together (e.g., bybraiding, weaving, cabling, etc.) to form lines 66 that extend outwardlyfrom the body 64. In this example, there are two such lines 66, but anynumber of lines (including one) may be used in other examples.

The lines 66 may be in the form of one or more ropes, in which case thefibers 62 could comprise splayed, frayed or finely divided ends of therope(s). In addition, the body 64 could be formed by one or more knotsin the rope(s). In some examples, the body 64 can comprise a fabric,yarn or cloth, the body could be formed by one or more knots in thefabric, yarn or cloth, and the fibers 62 could extend from the fabric,yarn or cloth.

In other examples, the device 60 could comprise a single sheet ofmaterial, or multiple strips of sheet material. The device 60 couldcomprise one or more films. The body 64 and lines 66 may not be made ofthe same material, and the body and/or lines may not be made of afibrous material.

Each of the body 64, the lines 66 and the fibers 62 could comprise adegradable material, a non-degradable material or a combination ofdegradable and non-degradable materials. For example, the body 64 couldbe degradable in the well, and the lines 66 and fibers 62 could benon-degradable, or vice-versa.

In the FIG. 9A example, the body 64 is formed by a double overhand knotin a rope, and ends of the rope are frayed, so that the fibers 62 aresplayed outward. In this manner, the fibers 62 will cause significantfluid drag when the device 60 is deployed into a flow stream, so thatthe device will be effectively “carried” by, and “follow,” the flow.

However, it should be clearly understood that other types of bodies andother types of fibers may be used in other examples. The body 64 couldhave other shapes, the body could be hollow or solid, and the body couldbe made up of one or multiple materials. The fibers 62 are notnecessarily joined by lines 66, and the fibers are not necessarilyformed by fraying, splaying or finely dividing ends of ropes or otherlines. The body 64 is not necessarily centrally located in the device 60(for example, the body could be at one end of the lines 66). Thus, thescope of this disclosure is not limited to the construction,configuration or other details of the device 60 as described herein ordepicted in the drawings.

In some examples, a knot or other enlarged body 76 (see, e.g., FIG. 19)could be tied or otherwise located in or on each of the strands or lines66 protruding from the main body 64. This configuration could provide asimilar sealing principle for leaks around the main body 64 attemptingto seal off an “un-round” opening or leak path. Once the strands orlines 66 start to displace through the leak path, a knot or otherenlarged body 76 on the strand would help seat/bridge the leak patharound the main body 64. This configuration could also aid in preventionof displacement of the device 60 due to higher differential pressures.The enlarged bodies 76 on the lines 66 could act as smaller (if they arein fact smaller than the body 64) plugging devices around a periphery ofthe opening being sealed. The enlarged bodies 76 on the lines 66 couldalso enhance fluid drag on the device 60, so that the device isinfluenced more to displace with the flow toward an opening or otherleak path.

Referring additionally now to FIG. 9B, another example of the device 60is representatively illustrated. In this example, the device 60 isformed using multiple braided lines 66 of the type known as “masontwine.” The multiple lines 66 are knotted (such as, with a double ortriple overhand knot or other type of knot) to form the body 64. Ends ofthe lines 66 are not necessarily frayed in these examples, although thelines do comprise fibers (such as the fibers 62 described above).

Referring additionally now to FIG. 10, another example of the device 60is representatively illustrated. In this example, four sets of thefibers 62 are joined by a corresponding number of lines 66 to the body64. The body 64 is formed by one or more knots in the lines 66.

FIG. 10 demonstrates that a variety of different configurations arepossible for the device 60. Accordingly, the principles of thisdisclosure can be incorporated into other configurations notspecifically described herein or depicted in the drawings. Such otherconfigurations may include fibers joined to bodies without use of lines,bodies formed by techniques other than knotting, etc.

Referring additionally now to FIGS. 11A & B, an example of a use of thedevice 60 of FIG. 9A to seal off an opening 68 in a conduit 72 isrepresentatively illustrated. In this example, the opening 68 is formedthrough a sidewall 70 of the conduit 72 (such as, a casing, liner,tubing, etc.). However, in other examples the opening 68 could beanother type of opening, and may be formed in another type of structure.

The device 60 is deployed into the conduit 72 and is conveyed throughthe conduit by fluid flow 74. The fibers 62 of the device 60 enhancefluid drag on the device, so that the device is influenced to displacewith the flow 74.

The fluid flow 74 may be the same as, or similar to, the flow of thefluid 12 described above for the examples of FIGS. 1-5, 7 & 8. However,the fluid flow 74 could be another type of fluid flow, in keeping withthe principles of this disclosure.

Since the flow 74 (or a portion thereof) exits the conduit 72 via theopening 68, the device 60 will be influenced by the fluid drag to alsoexit the conduit via the opening 68. As depicted in FIG. 11B, one set ofthe fibers 62 first enters the opening 68, and the body 64 follows.However, the body 64 is appropriately dimensioned, so that it does notpass through the opening 68, but instead is lodged or wedged into theopening. In some examples, the body 64 may be received only partially inthe opening 68, and in other examples the body may be entirely receivedin the opening.

The body 64 may completely or only partially block the flow 74 throughthe opening 68. If the body 64 only partially blocks the flow 74, anyremaining fibers 62 exposed to the flow in the conduit 72 can be carriedby that flow into any gaps between the body and the opening 68, so thata combination of the body and the fibers completely blocks flow throughthe opening. Additional knots or other enlarged bodies in or on thestrands or lines 66 may similarly block flow through the opening 68 asdiscussed above.

In another example, the device 60 may partially block flow through theopening 68, and another material (such as, calcium carbonate,poly-lactic acid (PLA) or poly-glycolic acid (PGA) particles) may bedeployed and conveyed by the flow 74 into any gaps between the deviceand the opening, so that a combination of the device and the materialcompletely blocks flow through the opening.

The device 60 may permanently prevent flow through the opening 68, orthe device may degrade to eventually permit flow through the opening.Removal or degrading of the device 60 may be useful when maintenance isperformed on the system 10 to mitigate the leak.

If the device 60 degrades, it may be self-degrading, or it may bedegraded in response to any of a variety of different stimuli. Anytechnique or means for degrading the device 60 (and any other materialused in conjunction with the device to block flow through the opening68) may be used in keeping with the scope of this disclosure.

In other examples, the device 60 may be mechanically removed from theopening 68. For example, if the body 64 only partially enters theopening 68, a cutting device may be used to cut the body from theopening.

Referring additionally now to FIGS. 12-14, additional examples of thedevice 60 are representatively illustrated. In these examples, thedevice 60 is surrounded by, encapsulated in, molded in, or otherwiseretained by, a retainer 80.

The retainer 80 aids in deployment of the device 60, particularly insituations where multiple devices are to be deployed simultaneously. Insuch situations, the retainer 80 for each device 60 prevents the fibers62 and/or lines 66 from becoming entangled with the fibers and/or linesof other devices.

The retainer 80 could in some examples completely enclose the device 60.In other examples, the retainer 80 could be in the form of a binder thatholds the fibers 62 and/or lines 66 together, so that they do not becomeentangled with those of other devices.

In some examples, the retainer 80 could have a cavity therein, with thedevice 60 (or only the fibers 62 and/or lines 66) being contained in thecavity. In other examples, the retainer 80 could be molded about thedevice 60 (or only the fibers 62 and/or lines 66).

During or after deployment of the device 60 into the system 10, theretainer 80 dissolves, melts, disperses or otherwise degrades, so thatthe device is capable of sealing off an opening 68, as described above.For example, the retainer 80 can be made of a material 82 that degradesin a process environment.

The retainer material 82 may degrade after deployment, but beforearrival of the device 60 at the opening 68 to be plugged. In otherexamples, the retainer material 82 may degrade at or after arrival ofthe device 60 at the opening 68 to be plugged. If the device 60 alsocomprises a degradable material, then preferably the retainer material82 degrades prior to the device material.

The material 82 could, in some examples, melt at elevated processtemperatures. The material 82 could be chosen to have a melting pointthat is between ambient temperature and a temperature at the opening 68,so that the material melts during transport from the deploymentapparatus 30 to the location of the opening.

The material 82 could, in some examples, dissolve when exposed to thefluid 12. The material 82 could be chosen so that the material beginsdissolving as soon as it is deployed into the system 10 and contacts acertain fluid (such as, water, brine, hydrocarbon fluid, acids, bases,etc.) therein. In some examples, the fluid that initiates dissolving ofthe material 82 could have a certain pH range that causes the materialto dissolve.

Note that it is not necessary for the material 82 to melt or dissolve inthe system 10. Various other stimuli (such as, passage of time, elevatedpressure, flow, turbulence, etc.) could cause the material 82 todisperse, degrade or otherwise cease to retain the device 60. Thematerial 82 could degrade in response to any one, or a combination, of:passage of a predetermined period of time in the system 10, exposure toa predetermined temperature in the system, exposure to a predeterminedfluid in the system, and exposure to a predetermined chemicalcomposition in the system. Thus, the scope of this disclosure is notlimited to any particular stimulus or technique for dispersing ordegrading the material 82, or to any particular type of material.

In some examples, the material 82 can remain on the device 60, at leastpartially, when the device engages the opening 68. For example, thematerial 82 could continue to cover the body 64 (at least partially)when the body engages and seals off the opening 68. In such examples,the material 82 could advantageously comprise a relatively soft, viscousand/or resilient material, so that sealing between the device 60 and theopening 68 is enhanced.

Suitable relatively low melting point substances that may be used forthe material 82 can include wax (e.g., paraffin wax, vegetable wax),ethylene-vinyl acetate copolymer (e.g., ELVAX™ available from DuPont),atactic polypropylene, and eutectic alloys. Suitable relatively softsubstances that may be used for the material 82 can include a softsilicone composition or a viscous liquid or gel.

Suitable dissolvable materials can include PLA, PGA, anhydrous boroncompounds (such as anhydrous boric oxide and anhydrous sodium borate),polyvinyl alcohol, polyethylene oxide, salts and carbonates. Thedissolution rate of a water-soluble polymer (e.g., polyvinyl alcohol,polyethylene oxide) can be increased by incorporating a water-solubleplasticizer (e.g., glycerin), or a rapidly-dissolving salt (e.g., sodiumchloride, potassium chloride), or both a plasticizer and a salt.

In FIG. 12, the retainer 80 is in a cylindrical form. The device 60 isencapsulated in, or molded in, the retainer material 82. The fibers 62and lines 66 are, thus, prevented from becoming entwined with the fibersand lines of any other devices 60.

In FIG. 13, the retainer 80 is in a spherical form. In addition, thedevice 60 is compacted, and its compacted shape is retained by theretainer material 82. A shape of the retainer 80 can be chosen asappropriate for a particular device 60 shape, in compacted orun-compacted form.

In FIG. 14, the retainer 80 is in a cubic form. Thus, any type of shape(polyhedron, spherical, cylindrical, etc.) may be used for the retainer80, in keeping with the principles of this disclosure.

Referring additionally now to FIG. 15, another example of a deploymentapparatus 90 and an associated method are representatively illustrated.The apparatus 90 and method may be used with a system and methoddescribed herein, or they may be used with other systems and methods.

When used with the examples of the system 10 and method representativelyillustrated in FIGS. 1-5, 7 & 8, the apparatus 90 can be connectedbetween a pump (or other pressure or flow source) and the conduit 14.However configured, an output of the apparatus 90 is connected to theconduit 14, although the apparatus itself may be positioned a distanceaway from the conduit.

The apparatus 90 is used in this example to deploy the devices 60 intothe conduit 14. The devices 60 may or may not be retained by theretainer 80 when they are deployed. However, in the FIG. 15 example, thedevices 60 are depicted with the retainers 80 in the spherical shape ofFIG. 13, for convenience of deployment. The retainer material 82 can beat least partially dispersed during the deployment, so that the devices60 are more readily conveyed by fluid flow 96.

In certain situations, it can be advantageous to provide a certainspacing between the devices 60 during deployment, for example, in orderto efficiently plug multiple spaced apart openings. One reason for thisis that the devices 60 will tend to first plug openings that arereceiving highest rates of flow.

In addition, if the devices 60 are deployed too close together, some ofthem can become trapped between openings, thereby wasting some of thedevices. The excess “wasted” devices 60 might later interfere with otherprocess operations.

To mitigate such problems, the devices 60 can be deployed with aselected spacing. The spacing may be, for example, on the order of theaverage spacing between the openings. The apparatus 90 is desirablycapable of deploying the devices 60 with any selected spacing betweenthe devices.

Each device 60 in this example has the retainer 80 in the form of adissolvable coating material with a frangible coating 88 thereon, toimpart a desired geometric shape (spherical in this example), and toallow for convenient deployment. The dissolvable retainer material 82could be detrimental to the operation of the device 60 if it increases adrag coefficient of the device. A high coefficient of drag (Cd) cancause the devices 60 to be swept past openings, instead of sealing theopenings.

The frangible coating 88 is used to prevent the dissolvable coating fromdissolving during a queue time prior to deployment. Using the apparatus90, the frangible coating 88 can be desirably broken, opened orotherwise damaged during the deployment process, so that the dissolvablecoating is then exposed to fluids that can cause the coating todissolve.

Examples of suitable frangible coatings include cementitious materials(e.g., plaster of Paris) and various waxes (e.g., paraffin wax, carnaubawax, vegetable wax, machinable wax). The frangible nature of a waxcoating can be optimized for particular conditions by blending a lessbrittle wax (e.g., paraffin wax) with a more brittle wax (e.g., carnaubawax) in a certain ratio selected for the particular conditions.

As depicted in FIG. 15, the apparatus 90 includes a rotary actuator 92(such as, a hydraulic or electric servo motor, with or without a rotaryencoder). The actuator 92 rotates a sequential release structure 94 thatreceives each device 60 in turn from a queue of the devices, and thenreleases each device one at a time into a conduit 86 that is connectedto the conduit 14.

Note that it is not necessary for the actuator 92 to be a rotaryactuator, since other types of actuators (such as, a linear actuator)may be used in other examples. In addition, it is not necessary for onlya single device 60 to be deployed at a time. In other examples, therelease structure 94 could be configured to release multiple devices ata time. In other examples, the release structure 94 could be in the formof an auger rotated by the rotary actuator 92. Thus, the scope of thisdisclosure is not limited to any particular details of the apparatus 90or the associated method as described herein or depicted in thedrawings.

In the FIG. 15 example, a rate of deployment of the devices 60 isdetermined by an actuation speed of the actuator 92. As a speed ofrotation of the structure 94 increases, a rate of release of the devices60 from the structure accordingly increases. Thus, the deployment ratecan be conveniently adjusted by adjusting an operational speed of theactuator 92. This adjustment could be automatic, in response to processconditions, opening parameters, flow rate variations, etc.

As depicted in FIG. 15, the fluid flow 96 enters the apparatus 90 fromthe left and exits on the right. Note that the flow 96 is allowed topass through the apparatus 90 at any position of the release structure94 (the release structure is configured to permit flow through thestructure at any of its positions).

When the release structure 94 rotates, one or more of the devices 60received in the structure rotates with the structure. When a device 60is on a downstream side of the release structure 94, the flow 96 thoughthe apparatus 90 carries the device to the right (as depicted in FIG.15) and into a restriction 98.

The restriction 98 in this example is smaller than the diameter of thedevice 60. The flow 96 causes the device 60 to be forced through therestriction 98, and the frangible coating 88 is thereby damaged, openedor fractured to allow the inner dissolvable material 82 of the retainer80 to dissolve.

Other ways of opening, breaking or damaging a frangible coating may beused in keeping with the principles of this disclosure. For example,cutters or abrasive structures could contact an outside surface of adevice 60 to penetrate, break, abrade or otherwise damage the frangiblecoating 88. Thus, this disclosure is not limited to any particulartechnique for damaging, breaking, penetrating or otherwise compromisinga frangible coating.

Referring additionally now to FIG. 16, another example of a deploymentapparatus 100 and an associated method are representatively illustrated.The apparatus 100 and method may be used with a system and methoddescribed herein, or they may be used with other systems and methods.

In the FIG. 16 example, the devices 60 are deployed using two flowrates. Flow rate A through two valves (valves A & B) is combined withFlow rate B through a pipe 102 depicted as being vertical in FIG. 16(the pipe may be horizontal or have any other orientation in actualpractice).

The pipe 102 may be connected to a pump or other fluid flow source. Insome examples, a separate pump (not shown) may be used to supply theflow 96 through the valves A & B.

Valve A is not absolutely necessary, but may be used to control a queueof the devices 60. When valve B is open the flow 96 causes the devices60 to enter the vertical pipe 102. Flow 104 through the vertical pipe102 in this example is substantially greater than the flow 96 throughthe valves A & B (that is, flow rate B>>flow rate A), although in otherexamples the flows may be substantially equal or otherwise related.

A spacing (dist. B) between the devices 60 when they are deployed intothe system can be calculated as follows: dist. B=dist. A*(ID_(A)²/ID_(B) ²)*(flow rate B/flow rate A), where dist. A is a spacingbetween the devices 60 prior to entering the pipe 102, ID_(A) is aninner diameter of a pipe 106 connected to the pipe 102, and ID_(B) is aninner diameter of the pipe 102. This assumes circular pipes 102, 106.Where corresponding passages are non-circular, the term ID_(A) ²/ID_(B)² can be replaced by an appropriate ratio of passage areas.

The spacing between the plugging devices 60 in the system (dist. B) canbe automatically controlled by varying one or both of the flow ratesA,B. For example, the spacing can be increased by increasing the flowrate B or decreasing the flow rate A. The flow rate(s) A,B can beautomatically adjusted in response to changes in process conditions,opening parameters, flow rate variations, etc.

In some circumstances, the desired deployment spacing (dist. B) may begreater than what can be produced using a convenient spacing dist. A ofthe devices 60 and the flow rate A in the pipe 106. The deploymentspacing B may be increased by adding spacers 108 between the devices 60in the pipe 106. The spacers 108 effectively increase the distance Abetween the devices 60 in the pipe 106 (and, thus, increase the value ofdist. A in the equation above).

The spacers 108 may be dissolvable or otherwise dispersible, so thatthey dissolve or degrade when they are in the pipe 102 or thereafter. Insome examples, the spacers 108 may be geometrically the same as, orsimilar to, the devices 60.

Note that the apparatus 100 may be used in combination with therestriction 98 of FIG. 15 (for example, with the restriction 98connected downstream of the valve B but upstream of the pipe 102). Inthis manner, a frangible or other protective coating on the devices 60and/or spacers 108 can be opened, broken or otherwise damaged prior tothe devices and spacers entering the pipe 102.

Referring additionally now to FIG. 17, a cross-sectional view of anotherexample of the device 60 is representatively illustrated. The device 60may be used in any of the systems and methods described herein, or maybe used in other systems and methods.

In this example, the body of the device 60 is made up of filaments orfibers 62 formed in the shape of a ball or sphere. Of course, othershapes may be used, if desired.

The filaments or fibers 62 may make up all, or substantially all, of thedevice 60. The fibers 62 may be randomly oriented, or they may bearranged in various orientations as desired.

In the FIG. 17 example, the fibers 62 are retained by the dissolvable,degradable or dispersible material 82. In addition, a frangible coatingmay be provided on the device 60, for example, in order to delaydissolving of the material 82 until the device has been deployed into asystem (as in the example of FIG. 15).

The device 60 of FIG. 17 can be used for blocking flow through openingsin pressure conduits, heat exchangers, fractioning towers, otherconduits and other types of process equipment. One advantage of the FIG.17 device 60 is that it is capable of sealing on irregularly shapedopenings, perforations, leak paths or other passageways. The device 60can also tend to “stick” or adhere to an opening, for example, due toengagement between the fibers 62 and structure surrounding (and in) theopening. In addition, there is an ability to selectively seal openings.

The fibers 62 could, in some examples, comprise wool fibers. The device60 may be reinforced (e.g., using the material 82 or another material)or may be made entirely of fibrous material with a substantial portionof the fibers 62 randomly oriented.

The fibers 62 could, in some examples, comprise metal wool, or crumpledand/or compressed wire. Wool may be retained with wax or other material(such as the material 82) to form a ball, sphere, cylinder or othershape.

In the FIG. 17 example, the material 82 can comprise a wax (or eutecticmetal or other material) that melts at a selected predeterminedtemperature. A wax device 60 may be reinforced with fibers 62, so thatthe fibers and the wax (material 82) act together to block an opening orother passageway.

In the FIG. 18 example, the fibers 62 extend outwardly from the maincentral body of the flow conveyed plugging device 60. The fibers 62extending from the body may be joined together to form one or morelines, ropes, yarns or fabrics, as in the examples of FIGS. 9A-10. Theoutwardly extending fibers 62 may enhance fluid drag on the pluggingdevice 60 and/or may enhance an ability of the plugging device to sealoff irregular shaped openings.

Referring additionally now to FIG. 19, another example of the pluggingdevice 60 is representatively illustrated. This example is similar insome respects to the FIGS. 9A, 10 & 18 examples, in that the fibers 62extend outwardly from the main central body 64.

In the FIG. 19 example, the fibers 62 are joined together to formmultiple ropes, yarns, fabrics or other types of lines 66. In addition,enlarged bodies 76 are formed on the lines 66, such as, by tying knotsin the lines or otherwise enlarging a geometry of each of the lines.Note that, in this example, each of the enlarged bodies 76 is smallerthan the main central body 64.

The FIG. 19 example also includes a substance 79 therein for modifying adensity or buoyancy of the plugging device 60. The substance 79 couldcomprise a gas or other relatively low density material for reducing thebulk density of the plugging device 60. The substance 79 could comprisea relatively high density material for increasing the bulk density ofthe plugging device 60.

The substance 79 may be contained in an enclosure 78 positioned in thebody 64 or other location in the plugging device 60. The enclosure 78could, for example, comprise a bladder as described above, forpermitting pressure to be applied to the substance 79 in the enclosure(e.g., to allow a gas to change phase to a liquid in response toincreased pressure, and to allow the liquid to change phase to the gasin response to decreased pressure).

Alternatively, a change in volume of the enclosure 78 itself (such as,due to a change in pressure and/or temperature in a process) can in someexamples cause a corresponding change in bulk density or buoyancy of theplugging device 60 (e.g., as the volume expands, the bulk densitydecreases and buoyancy increases, and as the volume contracts, the bulkdensity increases and buoyancy decreases). However, note that it is notnecessary for the volume of the enclosure 78 to change significantly inresponse to changes in pressure or temperature as, for example, in thecase of gas-filled glass beads used to decrease the bulk density of theplugging device 60.

Referring additionally now to FIGS. 20 & 21, another example of thesystem 10 and method is representatively illustrated. In this example,the plugging devices 60 are contained within enclosures 42 positioned inthe conduit 14. The enclosures 42, with the plugging devices 60 therein,may be continuously, periodically or intermittently flowed through theconduit 14 with the fluid 12, or the enclosures 42 may be introducedinto the conduit (for example, using a deployment apparatus 30, 90, 100)upon detection of an undesired opening 20 or leakage of the fluid 12from the conduit (for example, using the detection equipment describedabove).

The enclosure 42 may be in the form of a wrapper, bag, balloon, membraneor sheet material. The enclosure 42 may be degradable, self-degrading ornon-degradable. The enclosure 42 may be similar to any of thosedescribed in US Publication Nos. 2017/0030169, 2017/0275965 and2017/0260828, the entire disclosures of which are incorporated herein bythis reference.

The enclosure 42 may be tied or tethered, so that the enclosure and theplugging devices 60 therein are continuously exposed to the fluid 12flow. As depicted in FIG. 20, one of the enclosures 42 is secured to aninterior surface of the conduit 14 by a tether 44. The enclosure 42 maybe released in response to detection of a leak through an undesiredopening 20 (such as, in response to a pressure decrease, a flow rateincrease, a temperature increase, etc., in the conduit 14, which may bedetected by the detection equipment).

The enclosures 42 (with the plugging devices 60 therein) may havedifferent bulk densities or buoyancies to facilitate plugging openingsat corresponding different vertical locations in the conduit 14.Alternatively, or in addition, a single enclosure 42 could have multipledevices 60 therein having different densities, buoyancies or sizes.

When an enclosure 42 with the devices 60 therein is conveyed by flow toan opening 20, the enclosure may initially engage the opening andthereby restrict flow through the opening. The enclosure 42 may thentear, break, burst or otherwise open, and thereby permit the devices 60to be released from the enclosure.

The released devices 60 can then engage the opening 20 to therebyprevent flow through the opening. One benefit of the enclosure 42 isthat it delivers a “concentrated” group of the devices 60 to the opening20 to be plugged, as depicted in FIG. 21. Any devices 60 that do notengage the opening 20 can be retrieved from the conduit 14 (for example,using the filter 24 of FIG. 3).

A drag coefficient of the device 60 in any of the examples describedherein may be modified appropriately to produce a desired result. Forexample, it may in some circumstances be desirable to preferentiallyblock openings in a certain location in a conduit. The location could beat the openings through which the most fluid 12 is leaking. For thesesituations and others, the device 60 shape, size, density and othercharacteristics can be selected, so that the device tends to be conveyedby flow to a certain location in the conduit.

A diameter of the device 60 and the free fiber 62 length can beappropriately selected, so that the device is more suited to stoppingand sealingly engaging openings anywhere along the interior of theconduit. The free fibers 62 of the FIGS. 9-11B & 19 examples greatlyincrease the ability of the device 60 to engage the first unblockedopening (or other leak path) it encounters.

In examples of the device 60 where a wax material (such as the material82) is used, the fibers 62 (including the body 64, lines 66, knots,etc.) may be treated with a treatment fluid that repels wax (e.g.,during a molding process). This may be useful for releasing the wax fromthe fibrous material after fracturing or otherwise compromising theretainer 80 and/or a frangible coating thereon.

Suitable release agents are water-wetting surfactants (e.g., alkyl ethersulfates, high hydrophilic-lipophilic balance (HLB) nonionicsurfactants, betaines, alkyarylsulfonates, alkyldiphenyl ethersulfonates, alkyl sulfates). The release fluid may also comprise abinder to maintain the knot or body 64 in a shape suitable for molding.One example of a binder is a polyvinyl acetate emulsion.

Broken-up or fractured devices 60 can have lower Cd. Broken-up orfractured devices 60 can have smaller cross-sections and can passthrough restrictions more readily.

The restriction 98 (see FIG. 15) may be connected in any line or pipethat the devices 60 are flowed through, in order to cause the devices tofracture as they pass through the restriction. This may be used to breakup and separate devices 60 into wax and non-wax parts. The restriction98 may also be used for rupturing a frangible coating covering a solublewax material 82 to allow water or other process fluids to dissolve thewax.

Fibers 62 may extend outwardly from the device 60, whether or not thebody 64 or other main structure of the device also comprises fibers. Forexample, a ball (or other shape) made of any material could have fibers62 attached to and extending outwardly therefrom. Such a device 60 willbe better able to find and cling to openings, holes or other leak paths,as compared to the ball (or other shape) without the fibers 62.

For any of the device 60 examples described herein, the fibers 62 maynot dissolve, disperse or otherwise degrade in the system 10. In suchsituations, the devices 60 (or at least the fibers 62) may be removedfrom the system 10 by swabbing, scraping, circulating, filtering orother mechanical methods.

In situations where it is desired for the fibers 62 to dissolve,disperse or otherwise degrade in the system 10, nylon is a suitable acidsoluble material for the fibers. Nylon 6 and nylon 66 are acid solubleand suitable for use in the device 60. At relatively low processtemperatures, nylon 6 may be preferred over nylon 66, because nylon 6dissolves faster or more readily.

Self-degrading fiber devices 60 can be prepared from poly-lactic acid(PLA), poly-glycolic acid (PGA), or a combination of PLA and PGA fibers62. Such fibers 62 may be used in any of the device 60 examplesdescribed herein.

Fibers 62 can be continuous monofilament or multifilament, or choppedfiber. Chopped fibers 62 can be carded and twisted into yarn that can beused to prepare fibrous flow conveyed devices 60.

PLA and/or PGA fibers 62 may be coated with a protective material, suchas calcium stearate, to slow its reaction with water and thereby delaydegradation of the device 60. Different combinations of PLA and PGAmaterials may be used to achieve corresponding different degradationtimes or other characteristics.

PLA resin can be spun into fiber of 1-15 denier, for example. Smallerdiameter fibers 62 will degrade faster. Fiber denier of less than 5 maybe most desirable. PLA resin is commercially available with a range ofmelting points (e.g., 140 to 365° F.). Fibers 62 spun from lower meltingpoint PLA resin can degrade faster.

PLA bi-component fiber has a core of high-melting point PLA resin and asheath of low-melting point PLA resin (e.g., 140° F. melting pointsheath on a 265° F. melting point core). The low-melting point resin canhydrolyze more rapidly and generate acid that will acceleratedegradation of the high-melting point core. This may enable thepreparation of a plugging device 60 that will have higher strength in aprocess environment, yet still degrade in a reasonable time. In variousexamples, a melting point of the resin can decrease in a radiallyoutward direction in the fiber.

All of the materials for making plugging devices 60 described in thisdisclosure can be in the form of staple fiber or filament that is formedinto yarn. The yarn can be then twisted or braided into cord or rope, ortwisted into a larger yarn that can be used directly to make pluggingdevices 60.

Use of staple fiber (e.g., chopped fiber) typically involves additionalpreliminary steps of carding and one or more drawing steps beforespinning into yarn. Open end spinning, ring spinning, and air jetspinning can be used to form the basic yarn from staple fiber. Open endspinning may be preferable, because it typically uses fewer drawingsteps than the other spinning techniques, and a heavier yarn (e.g.,thread count <4) can be made.

Multiple yarns can be twisted together to prepare plied yarn (e.g., 10ply or 12 ply) that can be used to make plugging devices 60. As analternative to plied yarns, DREF spinning (friction spinning), can beused to make a large-diameter yarn without a subsequent plying step.DREF spinning typically uses a monofilament as a base for the staplefiber to form around.

Staple fiber of thermoplastic polymers (e.g., nylon, polyester,polylactic acid, etc.) can be prepared by melt spinning. Polymers notamenable to melt spinning (e.g., rayon, polyaramid, acrylic,polybenzimidazole) may be dissolved in solvent and spun in either a wetor dry process for solvent removal. After spinning, drawing, crimping,and chopping steps produce a staple fiber that can be used in theyarn-spinning process.

Multiple different polymers can be spun into a single, multi-componentfiber. Various core-sheath cross sections are possible (e.g., singlecore, concentric or eccentric cross section; multiple core, “islands inthe sea” cross section; segmented pie cross section). Multi-componentfiber in this application can be used to prepare a fiber that hassufficient strength, while degrading in a reasonable time in processenvironments.

A single component fiber that rapidly degrades may not have sufficientmechanical properties on the time scale of maintenance operations.Conversely, a mono-component fiber with adequate mechanical propertiesmay degrade too slowly to be useful.

Polylactic acid (PLA) degradability is related to the degree ofcrystallinity and melting point of the polymer. For example,poly(L-lactic acid) is more crystalline and degrades slower thanpoly(D-lactic acid-co-L-lactic acid). In one example, these two types ofPLA can be used together in a bi-component fiber to adjust thedegradation rate over a wide temperature range.

In addition to the lower crystallinity PLA degrading faster, acidproduced by the hydrolysis will accelerate the degradation of thehigher-crystallinity PLA. The lower crystallinity PLA can be used as thesheath (as in fiber made for nonwoven cloth applications), or as thecore.

To further expand the usable temperature range available with PLA, othercombinations of polymers can be used. Potentially useful polymersinclude poly(glycolic acid), poly(lactic acid-co-glycolic acid),poly(paradioxanone), poly(ε-caprolactone), poly(L-lacticacid-co-ε-caprolactone), poly(L-lactic acid-co-trimethylene carbonate),poly(ε-caprolactone-co-glycolic acid-co-trimethylene carbonate),polybutylene succinate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate),poly(L-lactic acid-block-ethylene glycol), and polyethyleneterephthalate. In all of these examples, the acid produced by thefaster-degrading polymer can accelerate the degradation of the morestable polymer.

Polyester hydrolysis is catalyzed by both acids and bases, butbase-catalyzed hydrolysis is much faster. For low temperature processeswhere the desired degradation rate cannot be achieved by the spontaneoushydrolysis of the polyester, the degradation rate can be increased byadding a base or base precursor to the polymer before spinning thefiber, or by coating the fiber. Alkaline earth oxides and hydroxides,(e.g., calcium oxide, magnesium oxide, calcium hydroxide, magnesiumhydroxide), zinc oxide, sodium tetraborate, calcium carbonate,hexamethylenetetramine, and urea could be used for this purpose.

Combinations of water-soluble polymer and degradable polymer can be usedto make bi-component fibers with higher degradation rates thansingle-component fibers made from a degradable polymer. The degradablepolymers listed above can be used in combination with variouswater-soluble polymers, including polyethylene oxide, polyvinyl acetate,polyvinyl alcohol, methacrylic acid copolymers, copolymers of2-ethylhexyl acrylate and dimethylaminoethyl methacrylate, andsulfopolyesters.

For sealing openings in high-temperature processes (e.g., >300° F.),fibers made from common polymers, such as nylon-6 and polyethyleneterephthalate, may degrade too rapidly. In high-temperature processes,plugging devices 60 made with fibers comprising hydrolysis-resistantmaterials could be used.

Potentially suitable materials for use in high-temperature processesinclude carbon fiber, glass fiber, mineral fiber, ceramic fiber,meta-aramid fiber (e.g., Nomex), para-aramid fiber (e.g., Kevlar),polyacrylonitrile fiber (e.g., Orlon, acrylic, modacrylic),polyparaphenylene sulfide fiber (e.g., Ryton), polybenzanilide,polybenzimidazole fiber (e.g., PBI), polyethylene terephthalate, andfibers made from copolymers and blends. Natural fibers suitable for hightemperature include cotton, flax, hemp, sisal, jute, kenaf and coir.

Buoyancy of a plugging device 60 can be increased by incorporatingtherein a low density material. One suitable material is hollow spheres(such as hollow glass spheres). The low density material could beembedded in the body 64 of the plugging device 60, for example.

Ropes or lines 66 that comprise the plugging device 60 could haveselected densities, so that the resulting plugging device is positively,negatively or neutrally buoyant. Examples of such lines include GARLOCK™PTFE and GFO braided fiber, and X-TREMA™ braided line.

In situations where the fluid 12 comprises a gas, the plugging devices60 may have an increased surface area, an increased drag coefficient(such as, by providing longer fibers 62), and a decreased density, ascompared to plugging devices for use in liquids. The increased surfacearea, increased drag coefficient and decreased density enables theplugging devices 60 to be readily conveyed by gas flow, and more readilydispersed within a conduit or other process equipment.

It may now be fully appreciated that the above disclosure providessignificant advancements to the art of preventing leakage from fluidconduits. In examples described above, the plugging devices 60 caneffective block flow through undesired openings 20 in fluid conduits 14,with fluid 12 flow conveying the plugging devices to the openings.

The above disclosure provides to the art a method of plugging at leastone undesired opening 20 in a fluid conduit 14. In one example, themethod can comprise: introducing one or more plugging devices 60 intothe conduit 14; conveying the plugging devices 60 by flow to the opening20; and blocking the flow through the opening 20 with the pluggingdevices 60.

The introducing step can include continually, periodically orintermittently introducing the plugging devices 60 into the conduit 14,or introducing the plugging devices 60 into the conduit 14 in responseto an indication that a fluid 12 is leaking from the conduit 14. Theindication may selected from the group consisting of a pressure change,a flow rate change and a temperature change. The indication may bereceived by a controller 36 from a sensor 38, 40, and the controller 36activates a plugging device deployment apparatus 30, 90, 100 in responseto receipt of the indication.

The method may include retrieving the plugging devices 60; andre-introducing the plugging devices 60 into the conduit 14 after theretrieving step.

The “one or more” plugging devices 60 may comprise multiple pluggingdevices 60. The multiple plugging devices 60 may have respectivedifferent buoyancies, different sizes and/or different densities.

The plugging devices 60 may each comprise a detection device 28 thatindicates at least one of a presence, an identity and a characteristicof the respective plugging device 60.

Each of the plugging devices 60 may comprise a main body 64, with lines66 extending outwardly from the main body 64, and with at least oneenlarged body 76 in or on each of the lines 66. The enlarged bodies 76in or on the lines 66 may each be smaller than the main body 64.

The method may include changing a buoyancy of each of the pluggingdevices 60 in the conduit 14. The buoyancy changing may comprisechanging a phase of a substance 79 in each of the plugging devices 60.

The substance 79 may comprise a gas contained in an enclosure 78 in theplugging device 60. The phase change may be due to a change in at leastone of pressure and temperature in the conduit 14.

The “one or more” plugging devices 60 may comprise multiple pluggingdevices 60, and the conveying step may include conveying the pluggingdevices 60 in an enclosure 42 through the conduit 14. The blocking stepmay comprise releasing the plugging devices 60 from the enclosure 42.

A system 10 for plugging at least one undesired opening 20 in a fluidconduit 14 is also provided to the art by the above disclosure. In oneexample, the system 10 can include a deployment apparatus 30, 90, 100configured to introduce one or more plugging devices 60 into the conduit14; a sensor 38 that measures a physical parameter indicative of leakagefrom the conduit 14; and a controller 36 that activates an actuator 34,92 of the deployment apparatus 30, 90, 100 in response to receipt fromthe sensor 38 of an indication of leakage from the conduit 14.

The indication may be selected from the group consisting of a pressurechange, a flow rate change and a temperature change.

The system 10 may include a filter 24 that separates the pluggingdevices 60 from fluid 12 flow through the conduit 14.

The “one or more” plugging devices 60 may comprise multiple pluggingdevices 60, and the multiple plugging devices 60 may have respectivedifferent buoyancies, different sizes and/or different densities.

The plugging devices 60 may each comprise a detection device 28 thatindicates at least one of a presence, an identity and a characteristicof the respective plugging device 60.

Each of the plugging devices 60 may comprise a main body 64, with lines66 extending outwardly from the main body 64, and with at least oneenlarged body 76 in or on each of the lines 66. The enlarged bodies 76in or on the lines 66 may each be smaller than the main body 64.

A buoyancy of each of the plugging devices 60 may change in the conduit14. The buoyancy change may comprise a phase change of a substance 79 ineach of the plugging devices 60.

The substance 79 may comprise a gas contained in an enclosure 78 in theplugging device 60. The phase change may occur in response to a changein at least one of pressure and temperature in the conduit 14.

The “one or more” plugging devices 60 may be contained within anenclosure 42 conveyed by fluid 12 flow through the conduit 14. Theplugging devices 60 may be released from the enclosure 42 in response toengagement of the enclosure 42 with the opening 20.

Although various examples have been described above, with each examplehaving certain features, it should be understood that it is notnecessary for a particular feature of one example to be used exclusivelywith that example. Instead, any of the features described above and/ordepicted in the drawings can be combined with any of the examples, inaddition to or in substitution for any of the other features of thoseexamples. One example's features are not mutually exclusive to anotherexample's features. Instead, the scope of this disclosure encompassesany combination of any of the features.

Although each example described above includes a certain combination offeatures, it should be understood that it is not necessary for allfeatures of an example to be used. Instead, any of the featuresdescribed above can be used, without any other particular feature orfeatures also being used.

It should be understood that the various embodiments described hereinmay be utilized in various orientations, such as inclined, inverted,horizontal, vertical, etc., and in various configurations, withoutdeparting from the principles of this disclosure. The embodiments aredescribed merely as examples of useful applications of the principles ofthe disclosure, which is not limited to any specific details of theseembodiments.

In the above description of the representative examples, directionalterms (such as “above,” “below,” “upper,” “lower,” etc.) are used forconvenience in referring to the accompanying drawings. However, itshould be clearly understood that the scope of this disclosure is notlimited to any particular directions described herein.

The terms “including,” “includes,” “comprising,” “comprises,” andsimilar terms are used in a non-limiting sense in this specification.For example, if a system, method, apparatus, device, etc., is describedas “including” a certain feature or element, the system, method,apparatus, device, etc., can include that feature or element, and canalso include other features or elements. Similarly, the term “comprises”is considered to mean “comprises, but is not limited to.”

Of course, a person skilled in the art would, upon a carefulconsideration of the above description of representative embodiments ofthe disclosure, readily appreciate that many modifications, additions,substitutions, deletions, and other changes may be made to the specificembodiments, and such changes are contemplated by the principles of thisdisclosure. For example, structures disclosed as being separately formedcan, in other examples, be integrally formed and vice versa.Accordingly, the foregoing detailed description is to be clearlyunderstood as being given by way of illustration and example only, thespirit and scope of the invention being limited solely by the appendedclaims and their equivalents.

What is claimed is:
 1. A method of plugging at least one undesiredopening in a fluid conduit, the method comprising: introducing one ormore plugging devices into the conduit in response to an indication thata fluid is leaking from the conduit, in which the indication is receivedby a controller from a sensor, and the controller automaticallyactivates a plugging device deployment apparatus in response to receiptof the indication; conveying the plugging devices by flow to theopening; and blocking the flow through the opening with the pluggingdevices.
 2. The method of claim 1, in which the introducing comprisescontinually introducing the plugging devices into the conduit.
 3. Themethod of claim 1, in which the introducing comprises periodicallyintroducing the plugging devices into the conduit.
 4. The method ofclaim 1, in which the introducing comprises intermittently introducingthe plugging devices into the conduit.
 5. The method of claim 1, inwhich the indication is selected from the group consisting of a pressurechange, a flow rate change and a temperature change.
 6. The method ofclaim 1, further comprising: retrieving the plugging devices; andre-introducing the plugging devices into the conduit after theretrieving.
 7. The method of claim 1, in which the one or more pluggingdevices comprise multiple plugging devices, and in which the multipleplugging devices have respective different buoyancies.
 8. The method ofclaim 1, in which the one or more plugging devices comprise multipleplugging devices, and in which the multiple plugging devices haverespective different sizes.
 9. The method of claim 1, in which the oneor more plugging devices comprise multiple plugging devices, and inwhich the multiple plugging devices have respective different densities.10. The method of claim 1, in which the plugging devices each comprise adetection device that indicates at least one of a presence, an identityand a characteristic of the respective plugging device.
 11. The methodof claim 1, in which the one or more plugging devices comprises multipleplugging devices, and in which the conveying comprises conveying theplugging devices in an enclosure through the conduit.
 12. The method ofclaim 11, in which the blocking comprises releasing the plugging devicesfrom the enclosure.
 13. A method of plugging at least one undesiredopening in a fluid conduit, the method comprising: introducing one ormore plugging devices into the conduit, in which each of the pluggingdevices comprises a main body, with lines extending outwardly from themain body, and with at least one enlarged body in or on each of thelines; conveying the plugging devices by flow to the opening; andblocking the flow through the opening with the plugging devices.
 14. Themethod of claim 13, in which the enlarged bodies in or on the lines areeach smaller than the main body.
 15. A method of plugging at least oneundesired opening in a fluid conduit, the method comprising: introducingone or more plugging devices into the conduit; conveying the pluggingdevices by flow to the opening; blocking the flow through the openingwith the plugging devices; and changing a buoyancy of at least one ofthe plugging devices in the conduit, in which the buoyancy changingcomprises changing a phase of a substance in the at least one of theplugging devices.
 16. The method of claim 15, in which the substancecomprises a gas contained in an enclosure in the at least one of theplugging devices prior to insertion of the at least one of the pluggingdevices into the conduit.
 17. The method of claim 15, in which the phasechange is due to a change in at least one of pressure and temperature inthe conduit.
 18. A system for plugging at least one undesired opening ina fluid conduit, the system comprising: a deployment apparatusconfigured to introduce one or more plugging devices into the conduit; asensor that measures a physical parameter indicative of leakage from theconduit; and a controller that automatically activates an actuator ofthe deployment apparatus in response to receipt from the sensor of anindication of leakage from the conduit.
 19. The system of claim 18, inwhich the indication is selected from the group consisting of a pressurechange, a flow rate change and a temperature change.
 20. The system ofclaim 18, further comprising a filter that separates the pluggingdevices from fluid flow through the conduit.
 21. The system of claim 18,in which the one or more plugging devices comprise multiple pluggingdevices, and in which the multiple plugging devices have respectivedifferent buoyancies.
 22. The system of claim 18, in which the one ormore plugging devices comprise multiple plugging devices, and in whichthe multiple plugging devices have respective different sizes.
 23. Thesystem of claim 18, in which the one or more plugging devices comprisemultiple plugging devices, and in which the multiple plugging deviceshave respective different densities.
 24. The system of claim 18, inwhich the plugging devices each comprise a detection device thatindicates at least one of a presence, an identity and a characteristicof the respective plugging device.
 25. The system of claim 18, in whichthe one or more plugging devices are contained within an enclosureconveyed by fluid flow through the conduit.
 26. The system of claim 25,in which the plugging devices are released from the enclosure inresponse to engagement of the enclosure with the opening.
 27. A systemfor plugging at least one undesired opening in a fluid conduit, thesystem comprising: a deployment apparatus configured to introduce one ormore plugging devices into the conduit, in which each of the pluggingdevices comprises a main body, with lines extending outwardly from themain body, and with at least one enlarged body in or on each of thelines; a sensor that measures a physical parameter indicative of leakagefrom the conduit; and a controller that activates an actuator of thedeployment apparatus in response to receipt from the sensor of anindication of leakage from the conduit.
 28. The system of claim 27, inwhich the enlarged bodies in or on the lines are each smaller than themain body.
 29. A system for plugging at least one undesired opening in afluid conduit, the system comprising: a deployment apparatus configuredto introduce one or more plugging devices into the conduit; a sensorthat measures a physical parameter indicative of leakage from theconduit; and a controller that activates an actuator of the deploymentapparatus in response to receipt from the sensor of an indication ofleakage from the conduit, in which a buoyancy of at least one of theplugging devices changes in the conduit, and in which the buoyancychange comprises a phase change of a substance in the at least one ofthe plugging devices.
 30. The system of claim 29, in which the substancecomprises a gas contained in an enclosure in the at least one of theplugging devices prior to insertion of the at least one of the pluggingdevices into the conduit.
 31. The system of claim 29, in which the phasechanges in response to a change in at least one of pressure andtemperature in the conduit.